Intracochlear electrode arrays have been successfully utilised for many years as a stimulation mechanism for auditory prostheses. The function of the array is to provide electrical stimuli, by selecting one or more electrodes in the array and delivering a stimulus pulse to the electrodes, so as to produce an auditory percept in a patient.
The array is connected to a receiver-stimulator unit, which in turn typically communicates transcutaneously with an externally worn speech processor and sound transducer.
Over time, many different strategies have been applied both to analyse the speech and sound signals received by the transducer, and to provide appropriate stimuli to selected electrodes in the array so as to optimise the speech and sound perception of the patient.
All commercially available cochlear implants utilise electrode arrays in which the electrodes are substantially equally spaced along the length of the array.
Recently, due to an increased understanding of the physiology of the cochlear, a number of proposals have been made to provide and electrode array which is shaped so as to be located near the inner wall of the scala tympani. By position the array in such a location the electrical stimulation delivered by the electrodes to a particular site on the cochlea is more localised resulting in an improved system providing greater auditory perception to the patient.
It is an object of the present invention to provide an electrode array which improves the fidelity of the reproduction of the audio spectrum in the percept of the cochlear implant recipient, for a given number of electrodes.